In the last few years, single pixel cameras utilizing compressive sensing technologies have been developed. Single pixel cameras have the capability to reconstruct two dimensional (2D) images from sequential measurements using a single photo detector coupled with a spatial light modulator. This mode of operation is in contrast with traditional 2D image sensors (e.g., silicon based charge-coupled device (CCD), complementary metal oxide-semiconductor (CMOS) sensors for visible and near infrared imaging, and mercury cadmium telluride (MCT) and microbolometer imaging sensors for thermal imaging), which perform simultaneous spatial sampling.
Current digital light modulator (DLM) technologies for spatial light modulation include digital light processing (DLP), liquid crystal display (LCD) and liquid crystal on silicon (LCOS). However, none of these technologies available on the commercial market can achieve the switching requirements to perform the hundreds of thousands of measurements required to reconstruct a multi-mega-pixel image in a reasonably short amount of time.
One type of technology that could achieve the switching requirements (i.e., max binary switch frequency of approximately 32 kilohertz (kHz)) to reconstruct the image for a single pixel camera is a digital mirror device (DMD). However, the DMD is a micro-opto-electro-mechanical system (MOEMS) device that is complex and very expensive (e.g., $13,000 for a 1024×768 pixel DMD development kit). In addition, the DMD requires a complicated auxiliary controller circuitry to turn on and off each micromirror for every acquisition, which makes it bulky and inconvenient to integrate into a portable system.